In the following descriptions, the term “audio apparatus” represents a cassette tape recorder, a MP3, a CD player, a cellular phone, a PDA, a DMB, etc. According to the Korean patent application “wired remote controller for audio apparatus” laid-open number 0092121 (laid-open date: Oct. 24, 2001) which is adapted as a prior art of the present invention, a user voice from a microphone and an external sound from an audio apparatus are selectively outputted through a speaker of an ear phone, so that a language practice function and a song practice function are obtained.
FIG. 1 is a perspective view illustrating an earphone of an audio apparatus of the Korean patent number 0346314, and FIG. 2 is a circuit diagram of an electric construction of FIG. 1.
As shown in FIG. 1, an audio apparatus earphone unit comprises an earphone 3 having a microphone 1 and a speaker, a remote controller and a connection part 8 which connects an audio apparatus 10 including a cassette tape recorder and a remote controller 5. In the drawings, reference numeral 11 represents an input plug of an earphone and a microphone connected with the audio apparatus 10, and 12 represents a switch for operating and adjusting the audio apparatus 10.
Here, the remote controller 5 controls the operation of the audio apparatus 10 and adjusts the sound inputted into the audio apparatus 10 for thereby preventing any interference between the sound from the audio apparatus 10 and the user's voice inputted from the microphone 1.
As shown in FIG. 2, in the interior of the remote controller 5, a microphone volume switch 6 is connected at an output side of a microphone driving unit 20 which is adapted to driving the microphone 1, with the microphone volume switch 6 being designed to adjust the sound from the microphone 1, and with a variable resistor (VR) being provided in the microphone 1.
A voice input amplifier 23 is connected at an output side of the microphone volume switch 6, with the voice input amplifier 23 being formed of a voice chip IC capable of amplifying the voice signal inputted from the microphone 1. An output selection switch 25 is connected at an output side of the audio input amplifier 23 for selectively outputting a user's voice inputted from the microphone 1 and an output of the audio apparatus 10 inputted from the input plug 9 which connects the audio apparatus 10 and the remote controller 5.
A voice mixer 24 is connected between the input plug 9 and the speaker 2, with the input plug 9 being adapted to connect the audio apparatus 10 and the remote controller 5, for thereby outputting a user's voice from the microphone 1 and an output of the audio apparatus 10 to the speaker 2 through different paths, with the voice mixer 24 being formed of impedance matching resistors R2 and R3 of the speaker 2 for connecting an output of the audio apparatus 10 to the ground so as to prevent sound interference.
There is further provided a power unit 26 for supplying power to the speaker 2 in accordance with an operation of the output selection switch 25.
In the conventional art, while directly hearing the sound from the audio apparatus, the user can practice language or singing. However, the conventional art is not provided with an echo function when a user hears, so that it is impossible to achieve more effective sound effects.